The proposed work is the characterization of the Mn-oxidation states contained in the oxygen evolving cluster of photosystem II with the use of high resolution x-ray spectroscopy. The aim is to study the Mn-oxidation with photosystem II in different chemically prepared states. The work is a continuation of recently obtained results of the S1 state and can reveal information crucial to the understanding of the mechanisms involved in photosynthetic processes. The technique makes use of the chemical shifts in the Mn K_ emission and is independent of other techniques to characterize oxidation states, such as absorption edge spectroscopy and EPR spectroscopy. Our spectrometer, which is a largely improved version of a previous design, is well characterized and has shown excellent performance in previous experiments.